Well, SLRs will disappear for sure (and good riddance, in my opinion). There will be (and some would argue, already are) electronic viewfinders that make mirrors and little viewfinders obsolete. The very high end EVFs are way too costly for now but that will change. For some time I have imagined a 1:1 EVF that basically shows what's on the sensor, at the same resolution. With backlighting.
I guess the next grand frontier is adaptive optics. I imagine a camera firing a reference beam through the lens, receiving the scattered beam, and adjusting the imaging system to aim for maximum sharpness, as a function of subject distance.
I also imagine sensors that are not perfectly flat but perhaps actuated (via piezo) for small curvature corrections. I imagine an element in the lens that is piezo strained. Yes, nobody will be able to afford it for a good long while

This is a military application first, as are many of the most forward-thinking technologies.
I also imagine highly modular systems in which the camera body is basically the same but you can swap out the sensor, like the failed Leica Modul R system but much better!
Nothing particularly exciting is going to happen for a good long while though- the cameramakers are dueling over very minor incremental improvements now. There's just not much room for anybody to break out with new products within the current market and manufacturing methods.